Some heating, ventilation, and air conditioning systems (HVAC systems) may comprise a thermo-mechanical thermal expansion valve (TXV) that regulates passage of refrigerant through the TXV in response to a temperature sensed by a temperature sensing bulb of the TXV. The bulb of the TXV may be located generally on a compressor suction line near an outlet of an evaporator coil or otherwise be configured to be responsive to variations in temperature of refrigerant line temperatures. When an HVAC system comprising a TXV starts operation, the TXV will operate in response to the actual refrigerant line temperature which leads to a vacillation between overshooting and undershooting a desired superheat value until the system generally reaches a steady state of operation.
In other cases, an HVAC system may comprise a motorized electronic expansion valve (EEV) that may be controlled in a manner selected to reduce the above-described overshooting, undershooting, and/or vacillation. However, some HVAC systems that utilize EEVs utilize a last known good EEV position value as a basis for determining an EEV position for use at startup of the HVAC system. In some cases, the environmental conditions related to the HVAC system may have changed since a previous operation of the HVAC system during which the last known good value was determined, thereby rendering the last known good value a less than optimal basis for determining a startup position for the EEV.